CN112946758A - Non-contact capacitive train proximity sensor and working method thereof - Google Patents
Non-contact capacitive train proximity sensor and working method thereof Download PDFInfo
- Publication number
- CN112946758A CN112946758A CN202110114284.7A CN202110114284A CN112946758A CN 112946758 A CN112946758 A CN 112946758A CN 202110114284 A CN202110114284 A CN 202110114284A CN 112946758 A CN112946758 A CN 112946758A
- Authority
- CN
- China
- Prior art keywords
- module
- voltage
- digital signal
- conversion module
- fpga
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/088—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices operating with electric fields
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/15—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for use during transport, e.g. by a person, vehicle or boat
- G01V3/165—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for use during transport, e.g. by a person, vehicle or boat operating with magnetic or electric fields produced or modified by the object or by the detecting device
Landscapes
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Train Traffic Observation, Control, And Security (AREA)
Abstract
The invention discloses a non-contact capacitive train proximity sensor which comprises a first polar plate module, a second polar plate module, a differential impedance conversion module, a two-stage voltage amplification module, a high-pass filter module, a low-pass filter module, a first AD conversion module, a second AD conversion module, an FPGA module, a dual-port dynamic storage module and an alarm module, wherein the first polar plate module and the second polar plate module are arranged in parallel with the ground and are used for sensing the voltage of a railway contact net, and the input end of the differential impedance conversion module is respectively electrically connected with the first polar plate module and the second polar plate module and is used for converting the voltage difference between the voltage of the railway contact net sensed by the first polar plate module and the voltage of the railway contact net sensed by the second polar plate module into a single-ended voltage signal. The invention can solve the technical problems that the existing magnetic steel sensor cannot move due to fixed installation and consumes too much manpower and material resources in the installation process.
Description
Technical Field
The invention belongs to the technical field of railway operation safety, and particularly relates to a non-contact capacitive train proximity sensor and a working method thereof.
Background
Under the rapid development of railway information-based construction, a train proximity sensor is widely used in railway construction operation to monitor whether a train arrives, and meanwhile, constructors are reminded to evacuate before the train arrives, so that the train operation and personnel safety are guaranteed. The common train approach sensor adopts a magnetic steel sensor which is arranged on the inner side of a rail, when a train arrives, the train wheels cut a magnetic induction line of the magnetic steel sensor, and then pulse current is generated to serve as the train arrival indication.
However, the existing magnetic steel sensor has some non-negligible technical problems: firstly, the magnetic steel sensor is fixedly installed, once the magnetic steel sensor is installed, the magnetic steel sensor cannot move, and the magnetic steel sensor needs to be buried in a wire during installation, so that manpower and material resources are consumed too much; secondly, the magnetic steel sensor is arranged on the rail, so that the train wheels are easy to directly contact and roll the magnetic steel sensor once the installation position of the magnetic steel sensor is too high, and the running safety of the train is influenced; thirdly, after the train passes through the steel rail, a plurality of fine iron filings generated in the friction process are attached to the magnetic steel sensor, and in addition, along with the daily accumulation and the monthly accumulation, a plurality of ash layers are also accumulated on the magnetic steel sensor, so that the magnetic field intensity is influenced, and the magnetic steel sensor cannot normally detect; fourthly, the function is too single, and the train early warning device can only be used for detecting whether a train arrives or not and cannot realize the early warning of the train; fifthly, the magnetic steel sensor is expensive.
Disclosure of Invention
In response to the above-identified deficiencies in the art or needs for improvement, the present invention provides a non-contact capacitive train proximity sensor and a method of operating the same. Its aim at, solve current magnet steel sensor and lead to unable removal owing to adopt fixed mounting, and the installation consumes the too big technical problem of manpower and materials, and when magnet steel sensor mounted position was too high, can lead to train wheel direct contact and roll magnet steel sensor, thereby influence the technical problem of train operation safety, and because iron fillings and dust are attached to magnet steel sensor, can influence magnetic field intensity, and then lead to the technical problem of the unable normal detection of magnet steel sensor, and its function is too single, can only be used for detecting whether the train arrives, can't realize the technical problem of train early warning in advance, and magnet steel sensor's technical problem that the price is high.
In order to achieve the above object, according to one aspect of the present invention, there is provided a non-contact capacitive train proximity sensor, which is disposed at a position within 20 meters from a railway line, and includes a first pole plate module, a second pole plate module, a differential impedance conversion module, a two-stage voltage amplification module, a high-pass filtering module, a low-pass filtering module, a first AD conversion module, a second AD conversion module, an FPGA module, a dual-port dynamic storage module, and an alarm module, wherein the first pole plate module and the second pole plate module are both disposed parallel to the ground and are configured to sense a voltage of a railway catenary;
the input end of the differential impedance conversion module is electrically connected with the first pole plate module and the second pole plate module respectively and used for converting a voltage difference between the voltage of the railway contact network sensed by the first pole plate module and the voltage of the railway contact network sensed by the second pole plate module into a single-ended voltage signal, and the output end of the differential impedance conversion module is electrically connected with the two-stage voltage amplification module.
The two-stage voltage amplification module is used for amplifying the single-ended voltage signal from the differential impedance conversion module;
the output end of the two-stage voltage amplification module is respectively and electrically connected with the high-pass filtering module and the low-pass filtering module;
the high-pass filtering module is used for filtering low-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module and inputting the direct-current voltage signals obtained after filtering into the first AD conversion module;
the low-pass filtering module is used for filtering high-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module and inputting the direct-current voltage signals obtained after filtering into the second AD conversion module;
the first AD conversion module is electrically connected with the high-pass filtering module and used for converting the direct-current voltage signal obtained after the filtering of the high-pass filtering module into a first digital signal and inputting the first digital signal into the FPGA module;
the second AD conversion module is electrically connected with the low-pass filtering module and used for converting the direct-current voltage signal obtained after filtering by the low-pass filtering module into a second digital signal and inputting the second digital signal into the FPGA module;
the FPGA module is electrically connected with the first AD conversion module, the second AD conversion module and the alarm module and is used for determining whether the alarm module needs to be started to work or not according to a first digital signal from the first AD conversion module and a second digital signal from the second AD conversion module;
the dual-port dynamic storage module is electrically connected with the FPGA module and is used for storing a first digital signal and a second digital signal;
the alarm module is used for sending alarm information under the control of the FPGA module.
Preferably, the distance between the first plate module and the second plate module ranges from 20cm to 50 cm;
the first plate module and the second plate module have an area ranging from 100 cm square to 400 cm square.
Preferably, the first and second plate modules are copper plates;
the differential impedance conversion module is high-impedance input and low-impedance output, and input leakage current is pA level;
the two-stage voltage amplification module is formed by directly cascading two one-stage voltage amplification modules, and the amplification factor range of each one-stage voltage amplification module is 10-100 times;
the high-pass filtering module filters out signals with the frequency of 50Hz or below in the single-end voltage signals amplified by the two-stage voltage amplifying module.
The low-pass filtering module filters out signals with the frequency of more than 50Hz in the single-end voltage signals amplified by the two-stage voltage amplifying module.
In general, compared with the prior art, the non-contact capacitive train proximity sensor has the following advantages:
1. the invention can be fixedly installed and also can be movably installed at a position close to a railway, and the network access and wire burying treatment is not needed, so that the technical problems that the existing magnetic steel sensor cannot move due to the adoption of fixed installation and the installation process of wire burying consumes too much manpower and material resources can be solved;
2. according to the invention, through a non-contact capacitive design, namely two polar plates are adopted to monitor the voltage change of a railway contact network, whether a train arrives can be identified, the installation position can be fixedly installed or made into portable equipment according to the requirement, and the installation position only needs to be arranged at the periphery of a railway, so that the technical problem that when the installation position of the existing magnetic steel sensor is too high, the train wheels directly contact and roll the magnetic steel sensor, and the operation safety of the train is influenced can be solved.
3. According to the invention, whether the train arrives is monitored by adopting a mode of monitoring the electric field change of the contact net in a differential mode of the two polar plates, so that the iron chips and the ash layer do not influence the electric field.
4. The polar plate material adopted by the invention can be common copper plate, the dosage is less, and the price is low.
5. According to the invention, the electric field change of the contact net is monitored by monitoring the electric field change between the two polar plates, and the health state of power supply of the contact net, the lightning state around a railway and the like can be further analyzed by the principle, so that the functionality and the applicability of the sensor are further expanded.
6. According to the invention, the high-frequency signal and the low-frequency signal are separated through the high-pass filtering module and the low-pass filtering module, on the basis of ensuring a wide frequency spectrum range, the single-channel data calculation amount is reduced, and the calculation delay is reduced.
According to another aspect of the present invention, there is provided a method of operating a non-contact capacitive train proximity sensor, comprising the steps of:
(1) the FPGA module sets the sampling rates of the first AD conversion module and the second AD sampling module to be 10MHz and 1000Hz respectively, and sets a counter i to be 1;
(2) the FPGA module controls the first AD conversion module and the second AD sampling module to start working, and when the single sampling time of the first AD conversion module arrives, the first AD conversion module acquires a first digital signal set A at the ith timeiRespectively storing the digital signals (including 1000 digital signals) in the dual-port dynamic storage module, and acquiring a second digital signal set B acquired by the second AD conversion module at the ith time when the single sampling time of the second AD conversion module arrivesiRespectively (including 1000 digital signals) in a dual-port dynamic memoryStoring in a module;
(3) the FPGA module acquires a second digital signal set B from the dual-port dynamic storage moduleiAnd using digital low-pass filtering algorithm to collect the second digital signal B obtained at the ith timeiProcessing to obtain the ith acquired low-pass filtered second digital signal set Bi' and obtaining the i-th obtained low-pass filtered second set of digital signals BiThe amplitude of's;
(4) the FPGA module judges the second digital signal set B obtained in the step (3) and subjected to low-pass filtering for the ith timei' whether the amplitude is larger than a preset first threshold value, if so, entering the step (5), otherwise, returning to the step (2);
(5) the FPGA module calculates the second digital signal set B obtained in the step (3) and subjected to low-pass filtering for the ith timei' and judging whether the energy is larger than a preset second threshold value, if so, entering the step (6), otherwise, returning to the step (2);
(6) the FPGA module calculates the first digital signal set A acquired at the ith time by using a cross-correlation functioniAnd (3) a correlation coefficient between the correlation coefficient and each sample set in a plurality of preset sample sets, judging whether the maximum value of the obtained correlation coefficients is greater than a preset third threshold value, if so, entering the step (7), otherwise, returning to the step (2);
(7) the FPGA module further judges whether the correlation coefficient obtained in the step (6) is larger than a preset fourth threshold, if so, the step (8) is carried out, and if not, the step (10) is carried out;
(8) the FPGA module collects the first digital signal A acquired at the ith timeiAs a new sample set, and distributing a confidence coefficient for the new sample set;
(9) the FPGA module judges whether the total number of all the obtained sample sets is greater than a preset fifth threshold value, if so, the step (10) is carried out, and otherwise, the step (11) is carried out;
(10) the FPGA module arranges the obtained confidence coefficients of all the sample sets in a descending order and deletes the sample set corresponding to the minimum value of the confidence coefficients;
(11) the FPGA module judges whether the counter i is more than or equal to 3, if so, the step (12) is carried out, otherwise, the step (13) is carried out;
(12) the FPGA module calculates a first digital signal set A acquired at the ith timeiI-1 th acquisition of Ai-1And the i-2 th acquisition of Ai-2I.e. adding the voltage values of the 1000 digital signals included in each digital signal set, and determining whether there is the first digital signal set a acquired the ith timeiEnergy of>First digital signal set A obtained at the (i-1) th timei-1Energy of>First digital signal set A obtained at i-2 timesi-2If yes, entering step (13), otherwise entering step (14);
(13) the FPGA module controls the alarm module to send out pre-alarm information of train approach, and the step (15) is carried out;
(14) the FPGA module controls the alarm module to send out alarm information of train approaching, and the step (15) is carried out;
(15) and (3) the FPGA module sets a counter i to i +1, judges whether a shutdown instruction from a user is received or not, if so, the process is ended, and otherwise, the step (2) is returned.
Preferably, in step (2), the input of the first AD conversion module and the input of the second AD conversion module are both direct current voltage signals, and the obtaining process is as follows:
(a) the differential impedance conversion module respectively obtains the induced voltage of the railway contact network from the first pole plate module and the second pole plate module, and outputs the voltage difference between the first pole plate module and the second pole plate module to the two-stage voltage amplification module as a single-ended voltage signal;
(b) the two-stage voltage amplification module is used for amplifying the single-ended voltage signal from the differential impedance conversion module and respectively outputting the amplified single-ended voltage signal to the high-pass filtering module and the low-pass filtering module;
(c) the high-pass filtering module filters low-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module, the direct-current voltage signals obtained after filtering are input into the first AD conversion module, meanwhile, the low-pass filtering module filters high-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module, and the direct-current voltage signals obtained after filtering are input into the second AD conversion module.
Preferably, the digital low-pass filtering algorithm used in step (3) is an arithmetic mean filtering method or a recursive mean filtering method; the number of elements in each preset sample set in the step (6) and the first digital signal set A acquired at the ith timeiWherein the elements in the sample set comprise a plurality of second digital signals collected from the second AD conversion module at different times, and/or at different locations, and/or at different incoming directions, and/or at different climatic conditions, and/or at different train types, as the train approaches the non-contact capacitive train proximity sensor of the present invention.
Preferably, the confidence coefficient in step (8) is equal to the correlation coefficient obtained in step (6);
for the plurality of sample sets preset in step (6), the confidence coefficient of each sample set is 1.
Preferably, the pre-warning message in step (13) is used to indicate that a train is about to arrive, and the warning message in step (14) is used to indicate that a train has arrived.
In general, compared with the prior art, the working method of the non-contact capacitive train proximity sensor, which is conceived by the invention, can obtain the following beneficial effects:
1. the invention adopts the step (1), and the high sampling rate is set for the first AD conversion module and the low sampling rate is set for the second AD conversion module, so that the single sampling time can be shortened, the sampling point number and the calculation complexity can be reduced, and the alarm delay can be reduced under the condition of ensuring a sufficiently long sampling window.
2. The invention adopts the steps (3) and (4) by calculating the low-pass filtered second digital signal set B acquired at the ith timeiThe amplitude of the' pre-judges whether a train approaches or not, so that the calculation times of energy calculation in the step (5) and cross-correlation operation in the steps (6) and (7) can be reduced, the power consumption consumed by calculation is reduced, and the alarm delay is further reduced.
3. The invention is due to the adoption ofSteps (6) to (8) are used by assembling a first digital signal set AiAnd comparing the maximum value of the correlation coefficient between the maximum value and each sample set in a plurality of preset sample sets with a preset threshold value, updating the sample sets in real time, and configuring confidence coefficients for the updated sample sets, so that the arrival scenes of the train can be enriched, and the reliability of the method can be further improved.
4. According to the invention, the steps (12) to (14) are adopted, and the energy of the first digital signal set at different moments is dynamically monitored, so that two functions of pre-alarming and alarming are realized, and the technical problem that the existing magnetic steel sensor is too single in function, can only be used for detecting whether a train arrives, and cannot realize the early warning of the train is solved.
Drawings
FIG. 1 is a block schematic diagram of a non-contact capacitive train proximity sensor of the present invention;
fig. 2 is a flow chart of a method of operating a non-contact capacitive train proximity sensor of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in fig. 1, according to a first aspect of the present invention, a non-contact capacitive train proximity sensor is provided, which includes a first pole plate module 1, a second pole plate module 2, a differential impedance conversion module 3, a two-stage voltage amplification module 4, a high-pass filter module 5, a low-pass filter module 6, a first Analog-to-digital (AD) acquisition module 7, a second AD conversion module 8, an FPGA module 9, a dual-port dynamic storage module 10, and an alarm module 11. The non-contact capacitance type train approach sensor is arranged at a position within 20 meters of a railway line.
The first pole plate module 1 and the second pole plate module 2 are both arranged in parallel with the ground and used for sensing the voltage of a railway contact net; the distance between the first plate module 1 and the second plate module 2 ranges from 20cm to 50cm, and the area of the first plate module 1 and the second plate module 2 ranges from 100 cm square to 400 cm square. The input end of the differential impedance conversion module 3 is electrically connected with the first pole plate module 1 and the second pole plate module 2 respectively, and is used for converting a voltage difference between the voltage of the railway contact network sensed by the first pole plate module 1 and the voltage of the railway contact network sensed by the second pole plate module 2 into a single-ended voltage signal, and the output end of the differential impedance conversion module 3 is electrically connected with the two-stage voltage amplification module 4.
Specifically, the first and second plate modules 1 and 2 are metal plates having good electrical conductivity, preferably copper plates.
The differential impedance conversion module 3 is high impedance input and low impedance output, and input leakage current is pA level.
The two-stage voltage amplifying module 4 is used for amplifying the single-ended voltage signal from the differential impedance transformation module 3.
Specifically, the two-stage voltage amplifying module 4 is formed by directly cascading two one-stage voltage amplifying modules, and the amplification factor range of each one-stage voltage amplifying module is 10 to 100 times.
The output end of the two-stage voltage amplification module 4 is respectively and electrically connected with the high-pass filter module 5 and the low-pass filter module 6.
The high-pass filtering module 5 is configured to filter a low-frequency signal in the single-ended voltage signal amplified by the two-stage voltage amplifying module 4, and input a dc voltage signal obtained after filtering to the first AD conversion module 7.
Specifically, the high-pass filtering module 5 filters out a signal with a frequency of 50Hz or less from the single-ended voltage signal amplified by the two-stage voltage amplifying module 4.
The low-pass filtering module 6 is configured to filter a high-frequency signal in the single-ended voltage signal amplified by the two-stage voltage amplifying module, and input the dc voltage signal obtained after filtering to the second AD conversion module 8.
Specifically, the low-pass filtering module filters out a signal with a frequency of 50Hz or higher from the single-ended voltage signal amplified by the two-stage voltage amplifying module 4.
The first AD conversion module 7 is electrically connected to the high-pass filtering module 5, and is configured to convert the dc voltage signal obtained by filtering by the high-pass filtering module 5 into a first digital signal, and input the first digital signal into the FPGA module 9.
The second AD conversion module 8 is electrically connected to the low-pass filtering module 6, and is configured to convert the dc voltage signal obtained after filtering by the low-pass filtering module 6 into a second digital signal, and input the second digital signal into the FPGA module 9.
The FPGA module 9 is electrically connected to the first AD conversion module 7, the second AD conversion module 8, and the alarm module 11, and is configured to determine whether the alarm module 11 needs to be started according to the first digital signal from the first AD conversion module 7 and the second digital signal from the second AD conversion module 8.
The FPGA module 9 of the invention adopts 5CEFA5U19I7 chips of Intel corporation.
As a further preference, the non-contact capacitive train proximity sensor of the present invention may further comprise a dual port dynamic memory module 10 electrically connected to the FPGA module 9.
In the present invention, the dual-port dynamic memory module 10 adopts CY7C028 chip of CYPRESS corporation.
The FPGA module 9 of the present invention can also be used to add control information (i.e., read or write) and address information (i.e., a storage address) to the first digital signal from the first AD conversion module 7 and the second digital signal from the second AD conversion module 8 in sequence, and store the first digital signal and the second digital signal after adding information in the dual-port dynamic storage module 10.
The alarm module is used for sending alarm information in various alarm prompt modes under the control of the FPGA module, such as sound alarm, light alarm and the like, or transmitting the alarm information through a wireless module (such as a LORA module and a 4G module) and matching with other alarm systems to work.
According to another aspect of the present invention, there is provided a method for operating the contactless capacitive train proximity sensor, comprising the steps of:
(1) the FPGA module sets the sampling rates of the first AD conversion module and the second AD conversion module to be 10MHz and 1000Hz respectively, and sets a counter i to be 1;
the step has the advantages that the high sampling rate is set for the first AD conversion module, the low sampling rate is set for the second AD conversion module, the single sampling time can be shortened under the condition that a sufficiently long sampling window is ensured, and the alarm delay is reduced.
(2) The FPGA module controls the first AD conversion module and the second AD conversion module to start working (wherein the single sampling time of the first AD conversion module is set to be 10ms, the sampling interval of the first AD conversion module is set to be 2s, the single sampling time of the second AD conversion module is set to be 1s, and the sampling interval of the second AD conversion module is set to be 1.01s), and when the single sampling time of the first AD conversion module reaches, the first AD conversion module obtains the first digital signal set A at the ith timeiRespectively storing the digital signals (including 1000 digital signals) in the dual-port dynamic storage module, and acquiring a second digital signal set B acquired by the second AD conversion module at the ith time when the single sampling time of the second AD conversion module arrivesiRespectively storing the digital signals (including 1000 digital signals) in the dual-port dynamic storage modules;
the purpose of storing the digital signals in the dual-port dynamic storage module in the step is to perform cache processing on the digital signals.
In this step, the inputs of the first AD conversion module and the second AD conversion module are both direct current voltage signals, and the obtaining process is as follows:
(a) the differential impedance conversion module respectively obtains the induced voltage of the railway contact network from the first pole plate module and the second pole plate module, and outputs the voltage difference between the first pole plate module and the second pole plate module to the two-stage voltage amplification module as a single-ended voltage signal;
(b) the two-stage voltage amplification module is used for amplifying the single-ended voltage signal from the differential impedance conversion module 3 and respectively outputting the amplified single-ended voltage signal to the high-pass filtering module and the low-pass filtering module;
specifically, the two-stage voltage amplification module is formed by directly cascading two one-stage voltage amplification modules, and the amplification factor range of each one-stage voltage amplification module is 10 to 100 times.
(c) The high-pass filtering module filters low-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module, the direct-current voltage signals obtained after filtering are input into the first AD conversion module, meanwhile, the low-pass filtering module filters high-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module, and the direct-current voltage signals obtained after filtering are input into the second AD conversion module;
(3) the FPGA module acquires a second digital signal set B from the dual-port dynamic storage moduleiAnd using digital low-pass filtering algorithm to collect the second digital signal B obtained at the ith timeiProcessing to obtain the ith acquired low-pass filtered second digital signal set Bi' and obtaining the i-th obtained low-pass filtered second set of digital signals BiThe amplitude of' (i.e., the difference between the voltage maximum and the voltage minimum in the 1000 digital signals);
specifically, the digital low-pass filtering algorithm used in this step is an arithmetic mean filtering method or a recursive mean filtering method (also referred to as a moving average filtering method).
(4) The FPGA module judges the second digital signal set B obtained in the step (3) and subjected to low-pass filtering for the ith timei' whether the amplitude is larger than a preset first threshold value, if so, entering the step (5), otherwise, returning to the step (2);
specifically, the preset first threshold is 0.1 to 0.5 times the reference voltage of the second AD conversion module, and preferably 0.3 times the reference voltage.
The above steps (3) and (4) have the advantage that the low-pass filtered second set of digital signals B obtained by the i-th acquisition is calculatediThe amplitude of the' pre-judges whether a train approaches or not, so that the calculation times of energy calculation in the step (5) and cross-correlation operation in the steps (6) and (7) can be reduced, the power consumption consumed by calculation is reduced, and the alarm delay is further reduced.
(5) The FPGA module calculates the second digital signal set B obtained in the step (3) and subjected to low-pass filtering for the ith timei' energy (i.e. each digital signal set is encapsulated byAdding voltage values of 1000 included digital signals), and judging whether the energy is greater than a preset second threshold value, if so, entering the step (6), otherwise, returning to the step (2);
specifically, the preset first threshold is 100 times to 500 times, preferably 300 times, the reference voltage of the second AD conversion module.
(6) The FPGA module calculates the first digital signal set A acquired at the ith time by using a cross-correlation functioniAnd (3) a correlation coefficient between the correlation coefficient and each sample set in a plurality of preset sample sets, judging whether the maximum value of the obtained correlation coefficients is greater than a preset third threshold value, if so, entering the step (7), otherwise, returning to the step (2);
specifically, the preset third threshold value ranges from 0.2 to 0.7, and is preferably 0.5.
The number of elements in each preset sample set and the first digital signal set A obtained at the ith time in the stepiWherein the elements in the sample set comprise a plurality of second digital signals collected from the second AD conversion module at different times, and/or different locations, and/or different directions of arrival, and/or different climatic conditions, and/or different train types (train, passenger car, single train head, maintenance train, etc.) when a train approaches the non-contact capacitive train proximity sensor of the present invention.
(7) The FPGA module further judges whether the correlation coefficient obtained in the step (6) is larger than a preset fourth threshold, if so, the step (8) is carried out, and if not, the step (10) is carried out;
specifically, the preset fourth threshold value ranges from 0.7 to 0.9, and is preferably 0.8.
(8) The FPGA module collects the first digital signal A acquired at the ith timeiAs a new sample set, and distributing a confidence coefficient for the new sample set;
specifically, the confidence coefficient is equal to the correlation coefficient obtained in step (6).
For the plurality of sample sets preset in step (6), the confidence coefficient of each sample set is 1.
(9) The FPGA module judges whether the total number of all the obtained sample sets is greater than a preset fifth threshold value, if so, the step (10) is carried out, and otherwise, the step (11) is carried out;
specifically, the value of the fifth threshold ranges from 800 to 1200, preferably 1000.
(10) The FPGA module arranges the obtained confidence coefficients of all the sample sets in a descending order and deletes the sample set corresponding to the minimum value of the confidence coefficients;
the advantage of steps (7) to (10) is that the first digital signal is collected byiAnd comparing the maximum value of the correlation coefficient between the maximum value and each sample set in a plurality of preset sample sets with a preset threshold value, updating the sample sets in real time, and configuring confidence coefficients for the updated sample sets, so that the arrival scenes of the train can be enriched, and the reliability of the method can be further improved.
(11) The FPGA module judges whether the counter i is more than or equal to 3, if so, the step (12) is carried out, otherwise, the step (13) is carried out;
(12) the FPGA module calculates a first digital signal set A acquired at the ith timeiI-1 th acquisition of Ai-1And the i-2 th acquisition of Ai-2I.e. adding the voltage values of the 1000 digital signals included in each digital signal set, and determining whether there is the first digital signal set a acquired the ith timeiEnergy of>First digital signal set A obtained at the (i-1) th timei-1Energy of>First digital signal set A obtained at i-2 timesi-2If yes, entering step (13), otherwise entering step (14);
(13) the FPGA module controls the alarm module to send out pre-alarm information of train approach, and the step (15) is carried out;
the pre-warning information in this step is used to indicate that the train is about to arrive.
(14) The FPGA module controls the alarm module to send out alarm information of train approaching, and the step (15) is carried out;
the alarm information in this step is used to indicate that the train has arrived.
The steps (12) to (14) have the advantage that the energy of the first digital signal set at different moments is dynamically monitored, so that two functions of pre-alarming and alarming are realized, and the technical problem that the existing magnetic steel sensor is too single in function, can only be used for detecting whether a train arrives or not, but cannot realize early warning of the train is solved.
(15) And (3) the FPGA module sets a counter i to i +1, judges whether a shutdown instruction from a user is received or not, if so, the process is ended, and otherwise, the step (2) is returned.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (8)
1. A non-contact capacitive train proximity sensor is arranged at a position within 20 meters away from a railway line and comprises a first polar plate module, a second polar plate module, a differential impedance conversion module, a two-stage voltage amplification module, a high-pass filtering module, a low-pass filtering module, a first AD conversion module, a second AD conversion module, an FPGA module, a dual-port dynamic storage module and an alarm module, and is characterized in that,
the first pole plate module and the second pole plate module are both arranged in parallel with the ground and are used for sensing the voltage of a railway contact net;
the input end of the differential impedance conversion module is electrically connected with the first pole plate module and the second pole plate module respectively and used for converting a voltage difference between the voltage of the railway contact network sensed by the first pole plate module and the voltage of the railway contact network sensed by the second pole plate module into a single-ended voltage signal, and the output end of the differential impedance conversion module is electrically connected with the two-stage voltage amplification module.
The two-stage voltage amplification module is used for amplifying the single-ended voltage signal from the differential impedance conversion module;
the output end of the two-stage voltage amplification module is respectively and electrically connected with the high-pass filtering module and the low-pass filtering module;
the high-pass filtering module is used for filtering low-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module and inputting the direct-current voltage signals obtained after filtering into the first AD conversion module;
the low-pass filtering module is used for filtering high-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module and inputting the direct-current voltage signals obtained after filtering into the second AD conversion module;
the first AD conversion module is electrically connected with the high-pass filtering module and used for converting the direct-current voltage signal obtained after the filtering of the high-pass filtering module into a first digital signal and inputting the first digital signal into the FPGA module;
the second AD conversion module is electrically connected with the low-pass filtering module and used for converting the direct-current voltage signal obtained after filtering by the low-pass filtering module into a second digital signal and inputting the second digital signal into the FPGA module;
the FPGA module is electrically connected with the first AD conversion module, the second AD conversion module and the alarm module and is used for determining whether the alarm module needs to be started to work or not according to a first digital signal from the first AD conversion module and a second digital signal from the second AD conversion module;
the dual-port dynamic storage module is electrically connected with the FPGA module and is used for storing a first digital signal and a second digital signal;
the alarm module is used for sending alarm information under the control of the FPGA module.
2. The non-contact capacitive train proximity sensor of claim 1,
the distance between the first polar plate module and the second polar plate module ranges from 20cm to 50 cm;
the first plate module and the second plate module have an area ranging from 100 cm square to 400 cm square.
3. The non-contact capacitive train proximity sensor according to claim 1 or 2,
the first polar plate module and the second polar plate module are copper plates;
the differential impedance conversion module is high-impedance input and low-impedance output, and input leakage current is pA level;
the two-stage voltage amplification module is formed by directly cascading two one-stage voltage amplification modules, and the amplification factor range of each one-stage voltage amplification module is 10-100 times;
the high-pass filtering module filters out signals with the frequency of 50Hz or below in the single-end voltage signals amplified by the two-stage voltage amplifying module.
The low-pass filtering module filters out signals with the frequency of more than 50Hz in the single-end voltage signals amplified by the two-stage voltage amplifying module.
4. A method of operating a non-contact capacitive train proximity sensor according to any of claims 1 to 3, comprising the steps of:
(1) the FPGA module sets the sampling rates of the first AD conversion module and the second AD sampling module to be 10MHz and 1000Hz respectively, and sets a counter i to be 1;
(2) the FPGA module controls the first AD conversion module and the second AD sampling module to start working, and when the single sampling time of the first AD conversion module arrives, the first AD conversion module acquires a first digital signal set A at the ith timeiRespectively storing the digital signals (including 1000 digital signals) in the dual-port dynamic storage module, and acquiring a second digital signal set B acquired by the second AD conversion module at the ith time when the single sampling time of the second AD conversion module arrivesiRespectively storing the digital signals (including 1000 digital signals) in the dual-port dynamic storage modules;
(3) the FPGA module acquires a second digital signal set B from the dual-port dynamic storage moduleiAnd using digital low-pass filtering algorithm to collect the second digital signal B obtained at the ith timeiProcessing to obtain the ith acquired low-pass filtered second digital signal set Bi' and obtaining the i-th obtained low-pass filtered second set of digital signals BiThe amplitude of's;
(4) judging the ith time obtained in the step (3) by the FPGA moduleThe obtained low-pass filtered second set of digital signals Bi' whether the amplitude is larger than a preset first threshold value, if so, entering the step (5), otherwise, returning to the step (2);
(5) the FPGA module calculates the second digital signal set B obtained in the step (3) and subjected to low-pass filtering for the ith timei' and judging whether the energy is larger than a preset second threshold value, if so, entering the step (6), otherwise, returning to the step (2);
(6) the FPGA module calculates the first digital signal set A acquired at the ith time by using a cross-correlation functioniAnd (3) a correlation coefficient between the correlation coefficient and each sample set in a plurality of preset sample sets, judging whether the maximum value of the obtained correlation coefficients is greater than a preset third threshold value, if so, entering the step (7), otherwise, returning to the step (2);
(7) the FPGA module further judges whether the correlation coefficient obtained in the step (6) is larger than a preset fourth threshold, if so, the step (8) is carried out, and if not, the step (10) is carried out;
(8) the FPGA module collects the first digital signal A acquired at the ith timeiAs a new sample set, and distributing a confidence coefficient for the new sample set;
(9) the FPGA module judges whether the total number of all the obtained sample sets is greater than a preset fifth threshold value, if so, the step (10) is carried out, and otherwise, the step (11) is carried out;
(10) the FPGA module arranges the obtained confidence coefficients of all the sample sets in a descending order and deletes the sample set corresponding to the minimum value of the confidence coefficients;
(11) the FPGA module judges whether the counter i is more than or equal to 3, if so, the step (12) is carried out, otherwise, the step (13) is carried out;
(12) the FPGA module calculates a first digital signal set A acquired at the ith timeiI-1 th acquisition of Ai-1And the i-2 th acquisition of Ai-2I.e. adding the voltage values of the 1000 digital signals included in each digital signal set, and determining whether there is the first digital signal set a acquired the ith timeiEnergy of>First digital signal set obtained at i-1 timeAnd a isi-1Energy of>First digital signal set A obtained at i-2 timesi-2If yes, entering step (13), otherwise entering step (14);
(13) the FPGA module controls the alarm module to send out pre-alarm information of train approach, and the step (15) is carried out;
(14) the FPGA module controls the alarm module to send out alarm information of train approaching, and the step (15) is carried out;
(15) and (3) the FPGA module sets a counter i to i +1, judges whether a shutdown instruction from a user is received or not, if so, the process is ended, and otherwise, the step (2) is returned.
5. The operating method of the non-contact capacitive train proximity sensor according to claim 4, wherein in the step (2), the input of the first AD conversion module and the input of the second AD conversion module are both DC voltage signals, and the acquisition process is as follows:
(a) the differential impedance conversion module respectively obtains the induced voltage of the railway contact network from the first pole plate module and the second pole plate module, and outputs the voltage difference between the first pole plate module and the second pole plate module to the two-stage voltage amplification module as a single-ended voltage signal;
(b) the two-stage voltage amplification module is used for amplifying the single-ended voltage signal from the differential impedance conversion module and respectively outputting the amplified single-ended voltage signal to the high-pass filtering module and the low-pass filtering module;
(c) the high-pass filtering module filters low-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module, the direct-current voltage signals obtained after filtering are input into the first AD conversion module, meanwhile, the low-pass filtering module filters high-frequency signals in the single-ended voltage signals amplified by the two-stage voltage amplifying module, and the direct-current voltage signals obtained after filtering are input into the second AD conversion module.
6. The operating method of the non-contact capacitive train proximity sensor according to claim 4 or 5,
the digital low-pass filtering algorithm used in the step (3) is an arithmetic mean filtering method or a recursion mean filtering method;
the number of elements in each preset sample set in the step (6) and the first digital signal set A acquired at the ith timeiWherein the elements in the sample set comprise a plurality of second digital signals collected from the second AD conversion module at different times, and/or at different locations, and/or at different incoming directions, and/or at different climatic conditions, and/or at different train types, as the train approaches the non-contact capacitive train proximity sensor of the present invention.
7. The operating method of the non-contact capacitive train proximity sensor according to any one of claims 4 to 6,
the confidence coefficient in the step (8) is equal to the correlation coefficient obtained in the step (6);
for the plurality of sample sets preset in step (6), the confidence coefficient of each sample set is 1.
8. The method of operating a non-contact capacitive train proximity sensor according to claim 4,
and (4) the pre-alarm information in the step (13) is used for indicating that the train is about to arrive.
The alarm information in step (14) is used to indicate that a train has arrived.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110114284.7A CN112946758B (en) | 2021-01-28 | 2021-01-28 | Non-contact capacitive train proximity sensor and working method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110114284.7A CN112946758B (en) | 2021-01-28 | 2021-01-28 | Non-contact capacitive train proximity sensor and working method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112946758A true CN112946758A (en) | 2021-06-11 |
| CN112946758B CN112946758B (en) | 2022-06-10 |
Family
ID=76238286
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110114284.7A Active CN112946758B (en) | 2021-01-28 | 2021-01-28 | Non-contact capacitive train proximity sensor and working method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112946758B (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040178924A1 (en) * | 2001-06-08 | 2004-09-16 | Gifford Carl W. | Non-contact proximity sensor |
| CN2700166Y (en) * | 2004-04-29 | 2005-05-18 | 成都唐源科技有限责任公司 | On-line locating tube grade detection device for electrified railway contact system detection vehicle |
| US20060001547A1 (en) * | 2004-06-30 | 2006-01-05 | David Davenport | Apparatus and method for monitoring the output of a warning or indicator light |
| US20130062474A1 (en) * | 2010-05-31 | 2013-03-14 | Central Signal, Llc | Train detection |
| CN203288031U (en) * | 2013-05-06 | 2013-11-13 | 郭立君 | Portable electric propulsion train approach alarm |
| US20130311130A1 (en) * | 2011-02-14 | 2013-11-21 | The Secretary Of State For Business Innovation And Skills | Proximity sensor system |
| US20160306061A1 (en) * | 2013-04-09 | 2016-10-20 | Iee International Electronics & Engieering S.A. | Capacitive sensing device |
| CN107351730A (en) * | 2017-07-18 | 2017-11-17 | 中铁第四勘察设计院集团有限公司 | A kind of electric railway train does not power off automatic neutral-section passing system and its operation method |
| CN107703549A (en) * | 2017-09-26 | 2018-02-16 | 上海多点科技有限公司 | The method for eliminating electrical capacitance proximity sensor low frequency noises |
-
2021
- 2021-01-28 CN CN202110114284.7A patent/CN112946758B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040178924A1 (en) * | 2001-06-08 | 2004-09-16 | Gifford Carl W. | Non-contact proximity sensor |
| CN2700166Y (en) * | 2004-04-29 | 2005-05-18 | 成都唐源科技有限责任公司 | On-line locating tube grade detection device for electrified railway contact system detection vehicle |
| US20060001547A1 (en) * | 2004-06-30 | 2006-01-05 | David Davenport | Apparatus and method for monitoring the output of a warning or indicator light |
| US20130062474A1 (en) * | 2010-05-31 | 2013-03-14 | Central Signal, Llc | Train detection |
| US20130311130A1 (en) * | 2011-02-14 | 2013-11-21 | The Secretary Of State For Business Innovation And Skills | Proximity sensor system |
| US20160306061A1 (en) * | 2013-04-09 | 2016-10-20 | Iee International Electronics & Engieering S.A. | Capacitive sensing device |
| CN203288031U (en) * | 2013-05-06 | 2013-11-13 | 郭立君 | Portable electric propulsion train approach alarm |
| CN107351730A (en) * | 2017-07-18 | 2017-11-17 | 中铁第四勘察设计院集团有限公司 | A kind of electric railway train does not power off automatic neutral-section passing system and its operation method |
| CN107703549A (en) * | 2017-09-26 | 2018-02-16 | 上海多点科技有限公司 | The method for eliminating electrical capacitance proximity sensor low frequency noises |
Non-Patent Citations (2)
| Title |
|---|
| 于志刚 等: "接触网几何参数检测仪的原理及应用", 《山东科学》 * |
| 李文: "列车接近防护系统在神港站的应用", 《铁道通信信号》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112946758B (en) | 2022-06-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1232832C (en) | Electric power apparatus external insulative leakage current on-line monitoring system in converting station | |
| CN102608452B (en) | High speed train equipment state and electric energy quality monitoring system and method | |
| CN105223034B (en) | A kind of braking performance test method and its system | |
| CN106891914A (en) | Rail clip working state of system real-time monitoring device, system and method | |
| CN205880122U (en) | Railway link up line cord running state monitoring devices | |
| CN204064443U (en) | Based on the transformer fault prior-warning device of vibration transducer | |
| CN105136278A (en) | Bearing system acoustic fault detection device | |
| CN202330624U (en) | Partial discharge ultrasonic wave detection device | |
| CN107167673A (en) | A kind of sensor of detectable charge variation feature | |
| CN112946758B (en) | Non-contact capacitive train proximity sensor and working method thereof | |
| CN103901283A (en) | Device for monitoring lightning distance by the adoption of acousto-optic electromagnetic wave signal | |
| CN108680843A (en) | A kind of method for detection of partial discharge of switch cabinet based on Radio Transmission Technology | |
| CN108319181A (en) | A kind of road information monitoring and display system in real time | |
| CN109375015B (en) | Current drainage detection device and remote transmission system | |
| CN201028286Y (en) | Pipe real-time monitoring system | |
| CN205607928U (en) | Acoustic emission vibration detection device based on piezoceramics piece | |
| CN102411845A (en) | Piezoelectric magnetic-sensing traffic information comprehensive monitoring device | |
| CN210775630U (en) | Alternating current electrified railway train power-taking voltage quality inspection device | |
| CN112130197A (en) | Micro-vibration target detector | |
| CN207374555U (en) | A kind of battery of electric vehicle tracks of device and anti-theft system of electromotor car | |
| CN209182488U (en) | A kind of failure determination device | |
| CN201069458Y (en) | Lighting strike real time online monitoring system | |
| CN208110837U (en) | A kind of flow in park monitoring system | |
| CN103927883B (en) | Based on electrical impedance imaging vehicle detecting system and the detection method of pressure drag material | |
| CN203965641U (en) | A kind of infrasound signals harvester and system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |